The US Navy's Northrop Grumman X-47B

The US Navy's Northrop Grumman X-47B, a demonstration unmanned combat air vehicle (UCAV) designed for aircraft carrier deployment, is seen on display July 31, 2012 at Naval Air Station Patuxent River, Maryland. The autonomous aircraft has no tail, a maximum unrefueled range of over 2,000 miles...

The US Navy's Northrop Grumman X-47B, a demonstration unmanned combat air vehicle (UCAV) designed for aircraft carrier deployment, is seen on display July 31, 2012 at Naval Air Station Patuxent River, Maryland. The autonomous aircraft has no tail, a maximum unrefueled range of over 2,000 miles... (Paul J. Richards, Getty Images)

The US Navy's Northrop Grumman X-47B, a demonstration unmanned combat air vehicle (UCAV) designed for aircraft carrier deployment, is seen on display July 31, 2012 at Naval Air Station Patuxent River, Maryland. The autonomous aircraft has no tail, a maximum unrefueled range of over 2,000 miles...